German for any tea biscuit or cookie. Though "Keks" was originally intended to be a plural form of "Kek", it has become a singular form (proper plural is now "Kekse").
Invented by biscuit-manufacturer Bahlsen when he first introduced his Leibnitz biscuits around 1900. When people couldn't pronounce the english word "cakes", Bahlsen made up "Keks".

Not originally from World of Warcraft as some people think, 'kek' is the Korean approximation in english of laughter when typed on a Korean keyboard during Starcraft matches. As Starcraft was made by Blizzard as is world of warcraft, their connection to laughter in both games seems to be an homage of sorts.